Subsea power line communication is a special form of underwater communication. It is preferably used in exploring and exploiting gas and oil fields located at the seabed. Subsea communication is used, for example, for transmitting binary data between topside control sites and subsea wellheads. Gas and oil fields that are explored or exploited using electronic communication to the wellheads or to other electronic equipment are sometimes called “electronic fields” (e-fields).
In prior art, different techniques for subsea communication have been described. On the one hand, there are wired electric or optical connections, on the other hand there are wireless connections. The wired connections can be subdivided into a first group providing communication lines for electronic or optical connections separate from electric power and a second group utilising power lines for electronic communications. In the latter case, advantageously no separate communication lines are needed.
For example, in US 2005/0243983 A1, a modem for receiving and data from and to a conductor is described. It comprises an output drive for transmitting data to the conductor and impedance matching means for matching an impedance of a receiver input with an impedance of the conductor. A gain of the output drive, a receiver gain and the impedance of the receiver input are adjustable at this modem.
A programmable component (and thus the electronic device in which it is integrated) can reach an irregular state from which it cannot escape on its own. This can occur, for example, because of a programming error, because of certain environmental conditions such as heat, because of internal or external electronic interference, because of ageing of the component, because of electromigration, or because of a combination of these reasons. Besides, a programmable component can fail, because its software has been damaged, e.g. due to a flipped bit or a damaged cell in the command memory of the component. Any state in which an electronic component does not behave like it is supposed to is called a malfunction in the following.
If a programmable component, in particular of a subsea power line modem, is subject to a malfunction, it often suffices to restart the component or the whole device to reset the device into a fully operational state. This is usually performed using a so-called watchdog for monitoring the component. If the component does not fulfil a certain condition that is monitored by the watchdog, a restart is triggered by the watchdog. However, the circumstances that caused the malfunction persist and the irregular state may occur again sooner or later. Hence, the software of the programmable device should be updated as soon as possible.
For this purpose, known modems for subsea power line communication and other electronic devices provide a direct connection via an external port to reprogram the appropriate component. It is obvious that this is not possible under all circumstances. For example, if a subsea modem is already deployed on the seabed retrieving it for reprogramming means an enormous downtime for the subsea equipment, which is also expensive, because the oil/gas exploration/exploitation is out of service then, too.
Even if only a desktop electronic device is concerned, connecting the device to a programming unit takes much time, resulting in a significant downtime for the device.